Measuring Nitrate Extraction from a DSB

there is no wrong or right way...
what there is though is the best way for beginners to start and reading your list nemo, they are the best advice guidelines for beginners to start and get into the hobby without too much grief.
how ever once your tank is mature and thriving, and i mean happy inmates, no losses good bio-diversity then try and break away, but if one wants to do it another by all means

but in the interest of the newbie these guidelines work 99% more than other ways.

to give an example, i split my overflow into 3 as i believe that each has there own function and shouldnt be connected, my first goes to my ATS then that flows to DSB/LR sump with zeolites and bio-balls and then return sump, my second goes to a mechanical filter sump with skimmer, carbon etc and the 3rd to my cryptic zone and refuge, then all go to a return sump and back to the DT. i have an in tank DSB to suppliment the life that gets killed in the return pump. after years of reeefing this works for me and might be over kill but that way 33% of water only gets treated at any one time by one form of filtration.
 
riaan its pretty obvious then that he means supply most of the water first to a skimmer and allow some(by having a split overflow outlet) to pass over the dsb and back into tank...as your tank water cycles it will eventually skim this water anyway.

nemo you mean 15-20 cm right lol 15-20mm wont even be enough to house some members thumbs:p

and as for the caulerpa filter i can safely talk about it after using it for four years.when its at its prime it works the best! but you need a decent sized forest to take up all the nutrients and you cant trim it too much,advantages are its free tang food:thumbup:

but on the other hand sometimes they just dont take a liking to the initial few weeks and die off.like i said in my post above that even though i kept it successfully in this tank for over three years during the last year it simply refuses to survive...no idea as to why this is.

so its also a bit fragile same as a dsb but easier to manage as you know if its working its growing whereas a dsb its hard to gauge how well its working.
 
While the current thinking seems to be that sugar fine or finer partical size is best for DSB's, I have always thought that the slightly less fine 1-2mm partical size worked best for me.

The reason I've thought is that I've always considered a DSB to be an aerobic as well as an anaerobic filter. The top layers working aerobically while O2 is available but as it is depleted in lower sections becoming anaerobic.

I've also felt that a too fine bed hardly alows for any water penetration thus making filteration of any type limited. And then running the risk of putrifying.

I feel that the fine stuff is possibly best left to a refugium as a natural substrate for criters to live in, while a DSB should consist of slightly coarser stuff. Also that the DSB should have sections removed cleaned and replaced periodically.

Possibly the DSB's you've observed that are not very effective Nemo's are very fine and are thus,

a) leaving traces of nitrites due to low aerobic activity.

b) If little aerobicaly produced nitrates are being generated by the DSB, then they are being produced elsewhere on various other aerobic surfaces and due to not being able to reach anearobic parts of the bed, don't get removed. :)

Interested to know your thoughts.
 
Yeh

Bob the (reef)builder said:
While the current thinking seems to be that sugar fine or finer particle size is best for DSB's, I have always thought that the slightly less fine 1-2mm particle size worked best for me.

Agree 100's One point often misunderstood is that water does not actually move up and down the DSB substrate/Plenum. It is the diffusive flow that is important. (exchange of dissolved solutes) Very fine substrate restricts this process. Too course allows the o2 to penetrate too deep into the anaerobic zone.


The reason I've thought is that I've always considered a DSB to be an aerobic as well as an anaerobic filter. The top layers working aerobically while O2 is available but as it is depleted in lower sections becoming anaerobic.

On the Button

I've also felt that a too fine bed hardly allows for any water penetration thus making filtration of any type limited. And then running the risk of putrefying.

Commented above.

I feel that the fine stuff is possibly best left to a refugium as a natural substrate for critters to live in, while a DSB should consist of slightly coarser stuff. Also that the DSB be have sections removed cleaned and replaced periodically.

Exactly, and IMO a refuge should not have a deep substrate 15-20mm.

Possibly the DSB's you've observed that are not very effective Nemo's are very fine and are thus, a) leaving traces of nitrites due to low aerobic activity.

Most are Toooooo small for the bio load.

b) If little aerobically produced nitrates are being generated by the DSB, then they are being produced elsewhere on various other aerobic surfaces and due to not being able to reach anaerobic parts of the bed, don't get removed. :)

Whatcha think?
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I personally have had better success with a Denitrifier and a refuge. A denitrifier allows one to adjust the desired Nitrate level. so if you want to run your system at say 5ppm one adjusts the flow rate. Not so easy on a DSB.

But Ya i think we are mostly on the same page.
 
something interesting on the fine sand dsb ive noticed...when using playsand and similar size aroganite then even a 5cm layer seems to be enough for denitrification.

this falls inline with what bob is saying on particle size as theres virtually no aerobic layer with playsand.

im currently filling up my dsb in my 680lt tank and ive decided to use coarser aragonite as well as a some ceramic rings mixed in with the playsand,i feel this will give a better diversity of surfaces for bacteria and also worms etc that usually live in our dsbs,granted that not every creature likes to live in fine substrate.
 
@Falcon often the working and setup of a DSB and Refuge are confused and mingled together. I like to keep them apart. A DSB needs a big footprint whilst a Refuge can in comparison have a smaller footprint but contain a similar water volume due to depth.

I have to pop out to a job right now but will pick up on the subject on my return.
 
Nemos Janitor said:
@Falcon often the working and setup of a DSB and Refuge are confused and mingled together. I like to keep them apart. A DSB needs a big footprint whilst a Refuge can in comparison have a smaller footprint but contain a similar water volume due to depth.

I have to pop out to a job right now but will pick up on the subject on my return.
Click to expand...

post pics if its a marine job:razz:
 
Nemos Janitor said:
@Falcon often the working and setup of a DSB and Refuge are confused and mingled together. I like to keep them apart. A DSB needs a big footprint whilst a Refuge can in comparison have a smaller footprint but contain a similar water volume due to depth.
Click to expand...

Exactly. I also often used to think of them together but recently have been more inclined to think of them as separate entities with completely different jobs.

Although they can be overlapped, its not the optimal way of doing either.
 
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